Get an MP4 with the main video and audio for the iPhone, TV or console that skips your MKV file.
Converting MKV to MP4 trades Matroska's flexibility for a file that iPhones, televisions, consoles and browsers will play. The main video and audio normally come across. What may not are the extras: MP4 holds fewer subtitle formats and players handle fewer tracks, so additional languages, styled subtitles and chapters can be dropped.
Transfers use HTTPS, and files converted on the free tier are deleted within 24 hours, so the result is not a long-term archive. Quality depends on the source file, so open the MP4 file once before you share it.
MKV (Matroska Video)
An open, royalty-free container from the Matroska project, first released in 2002. One file can hold almost any codec plus many audio tracks, subtitle tracks, chapters and attachments such as fonts, which makes it popular for film rips and recordings.
MP4 (MPEG-4 Part 14)
A stricter container defined by the MPEG standards group. It expects a narrow set of codecs and offers only limited text subtitle support, and in exchange it gets hardware playback on iPhones, consoles, televisions and browsers that often reject Matroska.
A short 1280 × 720 clip with sound, saved as MKV, converted on indox.org
MKV suits archiving and MP4 is the more playable of the two, so treat the MP4 as a copy for your devices. Your own MKV stays as it is, with every track and subtitle, and the copies indox holds on the free tier are deleted within 24 hours.
A collection meant for a television or console is rarely one file. Add several MKV files in one visit, from your device, Dropbox, Google Drive or a URL, and download a separate MP4 for each.
An OBS screen recording or stream capture saved as MKV will not import into an editor that cannot read Matroska. Convert it here with nothing installed and no account for a single file, then bring the MP4 into your project.
Add the MKV by dropping it on the box, browsing your device, or importing from Dropbox, Google Drive or a URL. First note which audio language and subtitles you rely on, because extras may not carry across.
Confirm that the output reads MP4 and set the conversion going. A progress bar follows the job, and you can cancel it if you picked the wrong title from your library.
Once the MP4 is on your device, check which audio track plays and whether subtitles appear. Image-based PGS or VobSub and styled ASS subtitles may be missing, and only the default audio language may remain.
You get an MP4 that Apple's players, many smart TVs, game consoles and web browsers accept without extra software, where they reject or only partly support Matroska. The main picture and soundtrack normally carry over. The extras are less certain: additional audio languages, image-based or styled subtitles, chapters and font attachments may be dropped, so check the result before you rely on it. There is nothing to install and no account to create for a single file.
The upload box shows the live size limit before you add a file. Signing in raises it, and paid plans raise it further.
MKV in, MP4 out. Pick another output on the converter if you need a different format.
Files are encrypted in transit over HTTPS and processed on indox infrastructure.
Free-tier files are deleted automatically within 24 hours after the job finishes.
| What you see | Why | What to do |
|---|---|---|
| There are no subtitles in the MP4 | Only one subtitle stream is picked automatically, and it has to be text-based | Keep the MKV when you need every subtitle track |
| The wrong language plays | Only one audio stream is picked automatically, the one with the most channels | Keep the MKV, or use a tool that lets you choose the track |
| The picture looks softer than the MKV | Video that MP4 cannot take as it is is re-encoded to H.264, and every re-encode costs a little detail | Keep the MKV as the master and use the MP4 only as a copy for devices |
| Fonts or cover pictures stored in the MKV are gone | Attachment streams are not selected automatically | Keep the MKV; the MP4 carries no attachments |
Older video files at a smaller size
iPhone and Mac video that plays anywhere
Browser recordings you can share
The sound from a video
| Compared on | MKV | MP4 |
|---|---|---|
| Structure | Built on EBML, a purpose-built multimedia wrapper | The MPEG-4 file format, with an object-based design |
| Subtitles | A defined subtitle track type; subtitles and captions are well supported | Check the converted file for the subtitle tracks you need |
| Chapters and attachments | Chapters, tags and attachments such as cover art are part of the structure | Check the converted file for the extras you need |
| Browser support | Not in MDN's list of container formats for the web | Supported by all browsers |
Facts checked on October 16, 2026
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Not necessarily. Both are containers, and when the MKV already holds H.264 or HEVC video with AAC audio, those streams can in principle be moved into MP4 bit for bit. Quality only drops when a stream has to be re-encoded because MP4 players would not handle it, which is most often the audio track.
Plain text subtitles such as SRT have the best chance, because MP4 has a timed-text track type they map onto. Blu-ray PGS and DVD VobSub subtitles are images, and ASS subtitles depend on styling and fonts, so neither fits the MP4 text model. Expect those to be dropped, simplified to bare text, or needing to be burned in.
Because the manufacturer chose not to support the container, or supports only some of what it can hold. Apple's built-in players do not read Matroska at all. Many televisions open MKV but then fail on a DTS soundtrack or a subtitle type, giving video with no sound. MP4 with H.264 and AAC avoids both problems.
They may not all survive. MP4 is able to store several audio streams, but support in players is uneven, and a conversion may keep only the default track. If you need a particular language or the commentary, check which track plays in the result. The same caution applies to chapters, which MP4 handles in a more limited way.
Neither is better in picture quality, since the container does not determine how the video looks. MKV is the more capable box, with room for any codec, unlimited tracks and rich subtitles, which suits archiving. MP4 is the more playable one. The usual pattern is to keep MKV as the master and make MP4 copies for devices.
No, that does not work. Matroska and MP4 arrange their data in completely different structures, so a renamed file is still Matroska and most players that refused it before will refuse it again. A few programs inspect the contents and ignore the name, which can make renaming look successful on one machine and fail on the next.
Drop files here
Add several at once. Documents, images, video and audio.